Fungal and aflatoxin contamination of some human food commodities in Nigeria

Abstract

This paper provides data of investigation of fungal, aflatoxins M1 (AFM1) and B1 (AFB1) contamination of three hundred and forty three samples of five different food commodities from three States in Nigeria. Maize samples from Niger (43) and Kogi (50) States and dried yam chips (50) from Niger State were purchased and assessed for fungal contaminants. Seventy (30 each from the maize samples and 11 from yam chips) of the two hundred and forty five fungi isolated from the maize and dried yam chips samples (77 and 151 from maize from Niger and Kogi respectively, and 17 from yam chips) were screened for their mycotoxin producing potentials in albino mice. One hundred samples of imported powdered milk marketed in Lagos metropolis were also analyzed for AFM1 using column chromatography for clean up and thin layer chromatography coupled with a densitometer equipped with winCATs soft ware for quantification. The Aflatoxin B1 contents of fifty marketed samples each of beans and wheat from Minna were also determined using thin layer chromatography with visual estimation. Fusarium species, Aspergillus fumigatus and Aspergillus flavus were the major seed borne fungi in maize from the two States. While the predominant fungal contaminants of dried yam chips were Fusarium, Aspergillus and Mucor species. Toxicity screening results showed that 68.57% of the fungi tested were toxigenic and were mostly isolates of Aspergillus, Fusarium, Penicillium, Rhizopus and Mucor. AFM1 was detected in 19 samples out of the 100 milk samples analyzed at levels ranging from 0.02 - 0.41 µg/kg. AFB1 was found in 29 out of the 50 beans (63.5 - 106.2 µg/kg) samples analyzed while 54% of the 50 marketed wheat samples (102.9 - 198.4 µg/kg) were also contaminated with the toxin. While the AFM1 found in the milk samples were below the 0.5 µg/kg permitted by European Union, Codex Alimentarius Commission and National Agency for Food and Drug Administration and Control, Nigeria, the AFBI levels in beans and wheat were above the permissible limits of these regulatory agencies (4 - 5 µg/kg).